The internal combustion engine has become the workhorse of modern society and is found in all parts of the world. Despite continual improvement over the years in the design and the operation of the engine, there are some parts which have remained essentially the same since the first engines were built.
Two of these parts are the intake valve which is used to admit fresh air and gas for combustion, and the exhaust valve which exhausts the combustion products. While these valves have undergone some technical improvements such as hardening of the valve surface to reduce wear, they have changed little and are still associated with many problems in the operation of the internal combustion engine.
The problems associated with intake and exhaust valves are mainly due to the reciprocating motion of the valves. Once during each cycle the intake valve moves into the cylinder and returns, impacting against the valve seat with some force. The exhaust valve operates in a similar manner. Thus during each complete cycle of intake, compression, power and exhaust, these two valves cycle inward and then outward impacting the valve seats. These repeated impacts cause wear on the valve seats and the valves and cause vibration of the engine. Since many automobile engines have four, six or eight cylinders and operate at high rates of speed, these repeated impacts and vibrations cause much additional noise and, the additional vibrations cause stress cracks and wear out the valves and other parts more rapidly.
An additional problem is that these valves, the intake valve and the exhaust valve, are two additional parts that must be added to engines, not to mention their associated synchronizing parts. In modern manufacturing, reduction in the number of parts necessary to manufacture a product leads directly to a reduction in material costs, reduced weight of the product, which in turn means increased efficiency and miles per gallon.
Prior attempts to solve problems associated with intake and valves have suffered from various drawbacks. For example, Ferres, U.S. Pat. No. 1,095,565, describes a conical shaped rotary exhaust valve. However, the conical exhaust valve shown in Ferres is as massive as some of the engine cylinders and would add weight to the engine rather than reducing weight and increase material costs. Other examples of rotary valves shown in the prior art suffer from similar limitations. For example, Johnson, U.S. Pat. No. 1,515,052 shows a spool shaped rotary valve; Francis, U.S. Pat. No. 1,340,481 shows a tapered conical valve body; Whitten, U.S. Pat. No. 1,528,715 shows a cylindrical rotary valve; Russell, U.S. Pat. No. 1,284,463 shows a rotary axially tapered rotary valve; Mettson, U.S. Pat. No. 1,271,344 shows a cylindrical valve; Keller et al, U.S. Pat. No. 1,513,911 shows a solid shaft valve.
A further problem with prior art internal combustion engines and with the examples of the various rotary valve engines described above is that the opening of the inlet and exhaust ports on the engine is rigidly tied to movement of the crankshaft. It is desirable to be able to adjust the opening of the intake valve and the exhaust valve during operation of the engine to take into account various atmospheric conditions such as humidity and air pressure and to also take into account, temperature and loading of the engine. Present construction with the opening and closing of the inlet and exhaust valves rigidly, mechanically connected to rotation of the crankshaft does not allow for advancing the point in the intake cycle at which the intake valve opens or the point in the exhaust cycle at which the exhaust port opens.